Finding the Fourth Proportional to 498.78, 747.15 and 406.56

Step by Step Solution

1. Step 1: Write the proportion equation
   498.78 : 747.15 = 406.56 : x
2. Step 2: Convert to fraction form
   498.78/747.15 = 406.56/x
3. Step 3: Cross multiply
   498.78x = 747.15 × 406.56
4. Step 4: Simplify right side
   498.78x = 303,764.70
5. Step 5: Solve for x
   x = 303,764.70/498.78
6. Step 6: Final answer
   x = 609.01